I did this demo for my freediving club Active Divers (and if you aren’t following us on Insta yet, that’s what I am taking all these pretty pictures for!): 1.5l PET bottle with holes punched in every 2cm, then filled with water. Looks cool and works pretty well (except the second hole from the bottom up, which I punched in a part of the bottle’s wall that wasn’t vertical, so the resulting jet doesn’t come out horizontally in the beginning and messes up the picture. Should have thought that through before…).

Between the picture above and the one below, there are a couple of seconds of water running out of the bottle, so see how the changed pressure changed the shape of the jets?

Also I love how the jets become instable and break up into droplets. Isn’t this pretty?